Natural sesquiterpenoids

Abstract

The production of trans-p-farnesene by callus cultures of Humulus lupulus has been carried 0ut.l The insect juvenile hormone JH-I11 (1) and methyl (2E, 625')-farnesoate have been isolated from the Malaysian plant Cyprus iria. The JH-111, obtained from this plant, has the same 10R configuration as that found in insect species and may constitute a new plant defence mechanism against insects.2 The nerolidol derivatives (2)-( 6) have been isolated from Geigeria ~r n a t i v a . ~The aerial part of CaIea crocinervosa contains the novel tris-nor sesquiterpene lactone crocinervolide (7). 4 The structure of a new bis-butenolide obtained from a species of the genus Eremophila has been determined as (8).5 Two new indolosesquiterpenes C02Me (3) R' = H, R~ = Oval' (4) R' = OGlcAc, R2 =H (5) R' = OClc(Ac),, R2 = H 0 J2-P (7) Ang = k q ; Epang= %q0 ; Meacr= %,,, ; Mebu = % . ; 217 220 NATURAL PRODUCT REPORTS, I992 (59) (60) R = 0 (61) R = OH, H (64) R=a-OH (65) R=P-OH (67) R=CH,OH (69) (68) R = CHO, A2(3) (71) R=C02Me (72) R = CH,O(CO)

(2S,3S)-3-(3-Bromophenyl)-6,6-dimethyl-2-nitro-2,3,6,7-tetrahydrobenzofuran-4(5H)-one

“…Dihdrofurans are found in many naturally occurring compounds and are used as versatile intermediates in organic and natural product synthesis (Fraga, 1992;Lipshutz, 1986). Organocatalytic asymmetric domino reactions have received increasing attention in the synthetic community recently.…”

Metal-free addition of aliphatic carboxylic acids to cyanopropargyl alcohols: an access to new families of functionalized dihydrofurans and 3(2H)-furanones

“…11 2,3-Dihydrofurans are recognized as precursors for the asymmetric synthesis of tetrahydrofurans. [12][13][14][15][16] Synthetic approaches to 2,3-dihydrofurans involve the [4+1] cycloaddition of enones with diazo compounds, 17,18 the [3+2] cyclization of aldehydes with β-ketosulfides/βketosulfones. 11,[19][20][21] For this purpose, the ring closing reaction of 1,3-dicarbonyl compounds with alkenes is efficient as well.…”

Asymmetric Synthesis of 2,3‐Dihydrofurans by One‐Pot Michael Addition/I2‐Mediated Cyclization

“…Furans are one of the most important skeletons of oxygen containing heterocycles. A great number of furan derivatives have been widely used as starting materials to produce pharmaceutically and industrially important compounds The dihydrofuran skeleton is also a common structural unit found in natural products and biologically active compounds . Given their wide spectrum of applications in the field of drug discovery and agricultural research, the preparation of dihydrofuran derivatives has drawn considerable attention in the past decades.…”